Radiotelegraphy.



LRAYMoNn-BARKER. I RADIO TELEGRAPHY. APPLICATION FILED mg. 9. 1908.

1 1 39,226. 7 Patented May 11, 1915.

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E. RAYMOND-BARKER- RADIO TELEGRAPHY.

APPLICATION FILED ]AN.9, 1908.

1,139,226. Patented May 11, 1915.

3 SHEETS-SHEET 2.

Mai-P e t i J776'6377Z/&7 W BWAQ LLQQAM E. RAYMOND-BARKER.

RADIO TELEGRAPHW, APPL|CATION FILED JAN. 9, was.

1 1 3 9, ,226; Patented May 11, 1915.

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an amine PATENT OFFICE.

EDWARD RAYMOND-BARKER, 0F WIMIBLEDON, ENGLAND, ASSIGNOR TO THE AMALGA- MATED RADIO-TELEGRAPH COMPANY, LIMITED, OF LONDON, ENGLAND. 3

RADIOTELEGRAPHY.

Specification of Letters Patent.

Patented May 11, 1915.

Application filed January 9, 1908. Serial No. 410,014.

which the following is a specification.

This invention relates to radio-telegraphy, its object being the provision of a system in which the signals instead of being made up of long and short elements as is usual in wireless systems, are composed of approximately equal-time-value-elements.

According to this invention the signals are produced by waves of different lengths, the transmitting apparatus being arranged to transmit oscillations of two or more different wave-lengths and the receiving station correspondingly adapted to receive the same. The system according to this invention is particularly suitable for use in connection with receiving apparatus of the kind in which a telephone is used, and when so employed may be regarded as a twoor multi-tone radio-telegraphic system.

It is to be understood that the improved system, depending as it does upon the possibility of transmitting signals of definite wave-lengths, is primarily intended for use in connection with radiotelegraphic apparatus of the kind in which fine tuning is practically possible. Various systems have been suggested, but for the purpose of the following description the Poulsen system is referred to as typical of one capable of line selective tuning. As is'well known, in the main circuit containing an are.

The invention may be regarded as the application to a radio-telegraphic system in which fine selective tuning is possible of the equal-time-element system of working as opposed to the Morse system of short dots and long dashes.

The equal-time-element-system is in principle well known as applied to ordinary telegraphy, as for example, in the single needle sounder, Brights bell apparatus, the Kelvin siphon recorder, and in M. Aders photographic receiver, and the advantages gained over the Morse lon dash and short dot system in ordinary te egraphy are, by

this invention, gained for wireless work,

with the added advantage of increased secrecy of working.

-Various electrical arrangements may be made for carrying out the invention, and in the accompanying drawings:

Figures 1, 2, 3 and 4: illustrate, by way of example, various s stems of connections for transmitting signa s formed of elements of different wave-lengths. Figs. 5 and 6 show two systems of connections for receiving apparatus, and Figs. 7 and 8 are diagrams illustrating additional recording apparatus which may be used in conjunction with the receiving apparatus shown in Fig. 6.

In each of the examples of transmitting systems shown in Figs. 1, 2 and 3, the power is derived from one or more arcs provided with properly adjusted inductances and capacities so that oscillations of different wave-lengths may be emitted.

With reference first to Fig. 1, this shows inductance C in circuit with it. But the ad j ustment of these inductances and capacities is such that the wave emitted from the antenna B when placed'in circuit, say by the key A, with. one are, is of greater length than the wave correspondingly. emitted from the other circuit when the key A is employed.

The keys are shown in their normal or resting positions, and it will be seen that a back contact H is furnished in each case,

this back contact being in connection withan inductance C and capacity D forming an oscillatory circuit of feeble emissive power, but of the same period and damping rate as the antenna system. This second circuit is thrown into the arc circuit when the antenna is cut out by releasing the key.

The connections shown in Fig. 2 illustrate by way of example the employment of one are instead of two, and also show how the signaling can be accomplished manually from a simple form of sending key through the operation of electro-magnetic devices.

A is the double sending key controlling a battery J and local circuits a and b. In the local circuit a is an eleetro-magnet K, while a similar electro-magnet K is placed in the local circuit Z). The armature lever K of each of these electro-magnets controls three contacts is 70 working in conjunction with a corresponding set of contactsprings is 70 is 0 I6 I0 The arch F is supplied with current from generator mains G. If now the right hand key is depressed, the electro-magnet K is energized and pulls its armature down, raising all the top contacts k 7.2 70 into connection with the springs 70 is is respectively.

vThis throws into circuit with the antenna B the capacity D through the contact If, the Whole of the inductance C through the contact 7c and also places the inductance G into the generator circuit through the contact is. If the left sending key A bodepressed, the electromagnet K operates and throws into circuit, through the contacts 70 70 k operated by it, another capacity D and a portion only of the inductance C for it will be seen that the top contact spring is, instead of being in communication with the end of the inductance C as is the'correspending contact-spring k of the right hand side of the diagram, is connected through conductor 0 to a point about midway of that inductance. This is a convenient arrangement for obtaining from one are waves of two different lengths to be used as approximately'equal-time-value elements in a wireless sgnal. It will be appreciated that the bottom contacts 70 and 7c whereon the contacts 70 70 come to rest may throw into the arc circuit supplementary oscillatory circuits of feeble emissive powers for the same purpose as in the arrangement shown in and T) represent inductance and capacity, respectively, of appropriate value in a circuit shunted with respect to the arc and thrown into circuit when the contacts 10 la of the right hand lever rest upon the contacts 70 70. Similarly C and D represent inductance and capacity, respectively,

shunted with respect to the arc and thrown into circuit when the corresponding contacts 70 k of the left hand lever rest upon the contacts 70 is. The contacts 70 serve merely as back stops for the contacts 70 The connections shown in Fig. 3 illustrate byway of example one way in which automatic transmission may be applied to a wireless system giving signals composed of Waves of two different lengths, and also shows the use of the method suggested by Poulsen in which there is provided in the generatorcircuit or inthe antenna 011'- cuit, a non-inductive 'reslstance M large enough to keep down the oseillations,-signals being sent by short-circuiting this re sistanee. In this figure L indicates diagrammatically a perforated strip upon which the signals are punched in the well known way, the perforations working in conjunction with flexible brushes L L after the manner of a Delany automatic transmitter. For the purpose of illustration a' double sending key A is also shown, and it will be seen that'either the strip L or the key A can operate local circuits containing electro-magnets K and K controlling radiotelegraphic sending circuits. Two arcs F 2 are employed each provided with inductances C and capacities D*, the inductances C and non-inductive resistances M being provided in the generating circuit. It will be seen that the antenna B in this case is always in connection with each of the oscillatory circuits plus the large non-inductive resistances M, and that the action of the electro-magnets K and K is to cut out one or other of those non-inductive resistances so that an undamped oscillation will be supplementary contacts is is on the armatures of the electromagnets K K the siphon recorder diagrammatically illustrated at N may through a local circuit and batteries N be made to give a record of all outgoing signals. The receiving apparatus does not need detailed description. .The connections must comprise essentially two sets of apparatus, one capable of receiving oscillations of one wave-length and the other oscillations of another wave-length, the inductances and capacities of the two circuits being so adjusted that they are tuned to the wave-length of the oscillation emitted by the particular sending station. 'In the example of receiving connections shown in Fig. 5 the receiving antenna B is joined to earth through four circuits in parallel with each other,-two of these circuits containing inductances C and the other two capacities D. Each of the inductances C acts inductively upon another circuit, the inductance C and capacity D of which are so adjusted this instance to give visible signals on a siphon recorder instead of audible signals in a telephone. The circuits from the receiving antenna B to earth may be as described with reference to Fig. 5, but in the secondary circuits a wave-indicator or coherer T maaeae g is provided havinga tongue T kept in rapid vibration and acting as an interrupter so as to make intermittent connection between contacts 2, and Another vibrating 5' tongue or interrupter '1 works in conjunction with a contact t and between the contact t andt is a local circuit comprising a local battery 1 and a highly sensitive relay U preferably of the suspended-coil type. In

this arrangement the vibrationsfrom the primary coil 0 induce oscillations in the secondary coil C, and the vibrating tongues or interrupters T 'T are moved synchronously. For instance, they may be mounted mechanically together, say, on the end of one arm of a vibrating lever so that the two gaps in the local circuit containing the relay U and the battery J are closed simultaneously. The sensitive relays U will thus respond to oscillations received by the antenna B if such oscillations be of the proper wave-length to whichthe receiving apparatus is tuned. The response of each relay U maybe utilized in various ways to bring about a visible record of the received signals, and Figs. 7 and 8 illustratetwo convenient methods.

In Fig. 7 the two sensitive relays U are shown connected by a double or split battery 80 J their outer-terminals being connected by a conductor 7. -To the middle point J of the batt ery J is'connected one pole of a sensitive polarized relay V, the other pole being joined to the conductor f. The sta- 85 tionary contacts V and V of this polarized relay are joined to a local battery J, and from the middle point of such battery a conductor gleads to a siphon recorder N. The other pole of this recorder is connected by 40 a conductor h to the movable contact V of the polarized relay. In this system of connections it is only necessary for the sensitive relays U to have one fixed contact U working in conjunctionwith the moving contact U From the diagram it will be readily seen that according to which of the sensitive relays U is energized so will the movable contact V*- of the polarized relay V make connection with either the fixed contact V or V This polarized relay in fact acts as a battery-receiving key and governs the direction of the current from the local battery J through the recorder N thus, a signal record of the ordinary kind will be produced, upon the tape. The sensitive relays Uare shown as provided with condensers .U" across their contacts for lessening the sparking at the contact.

Fig. 8 shows another system of connections for bringing about the same result. In

this case the sensitive relays U are pro vided with two fixed contacts U and 'U working in conjunction with the movable contact U l/Vith this arrangement it will i be seen that the battery 5 need not be divided, for the sensitive relays U in this case act as double-current or reversing keys and determine which pole of the single battery J shall be connected to any one pole of the polarized relay V. This polarized relay is provided with a high resistance shunt V to prevent sparking at the contacts of the sensitive relays U, U. The connections between this polarized relay V and the siphon recorder N are substantially the same as described with reference to Fig. 7.

The above described transmitting and receiving systems and connections are given as examples showing howsignals composed of two difl'erent wave-lengths can be transmitted and received by radio-telegraphy either audibly as a two-tone message on a receiver or visibly, as on a siphon recordertape. Obviously, however, the invention may b carried out in other ways which are in themselves well known methods in ordinary telegraphic Work, the essential features being the provision of transmitting apparatus giving Waves of two or more different lengths and of receiving apparatus capable of receiving such waves and transmitting them into signals of preferably equal-time-value elements. Given such essentials, other. well known telegraphic operations may be carried out besides those already mentioned, such, for example, as the automatic relaying of messages from one long distance circuit to another, or the automatic perforation of messages on a strip of paper to be used for re-transmission.- It will, of course, be understood that the termequal-time-value-elementas used in this specification is intended to distinguish between wlmt is commonly regarded as a recorder or some like signal, and the long dash short dot Morse code. It does not necessarily follow that the signals formed by the oscillations of different wave-lengths would be in themselves equal, although they would probably be approximately equal. But in any case 'the difierence in the timevalue of the two signals would not be used for the purposes of distinguishing between a dot and a dash.

One of the principal advantages of the two-tone or two wave-length equal-timevalue-systemof radio-telegraphy is the great economy of time in signaling, an equal-timevalue signal being on the average nearly 30% than the ordinary long and short Morse signal.

Another advantage is that when acoustic signals are used a two-tone code is much more easily read than is the one-tone long and short code. This advantage is especially marked in the case of bad transmission whcre the time-value relationship between the dot and the dash is not adhered to; obviously in'two-tone signaling,

however fast the transmission, the contrast I between the dot and dash is independent of the operator.

What I claim and desire to secure by Letters Patent of the United States is 1. In radio-telegraphy, the combination With an elevated conductor system, electric arcingmeans, a pair of arc-shunting circuits containing capacity and inductance adjusted to produce undamped electrical oscillations of a known wave length, one of said shunt circuits being associated with the elevated conductor system, another pair of arc-shunting circuits adjusted to produce undamped electrical oscillations of a different wave length, one of said circuits being associated with the elevated conductor system, means for normally keeping the electric arcing means in connection with the arc-shunting circuits that are unassociated with the ele vated conductor system and means for breaking the aforesaid connections and making connections between the arcing means and the arc-shunting circuits that are associated with the elevated conductor system in a predetermined order and for equal intervals of time so that the elevated conductor system emits signals composed of elementsequal in time value but differing in Wave-length.

2. In radio-telegraphy, the combination with an elevated conductor. system, electric arcing means, a pair of arc-shunting circuits containing capacity and inductance adjusted to produce undamped electrical oscillations of a known wave length, one of said shunt circuits being associated with the elevated conductor system, another pair of arcshunting circuits adjusted to produce undamped electrical oscillations of a different Wave length, one of said circuits being associated with the elevated conductor system,

means for normally keeping the electric arc-' ing means in connection With the arc-shunting circuits that are unassociated-With the in presence of two Witnesses.

elevated conductor system, electromagnetic devices for actuating the aforesaid connecting means to break the aforesaid connections and to make connections between the arcing means and the arc-shunting circuits that are associated with the elevated conductor system, and means for actuating the said electromagnetic devices for equal intervals of time and in a predetermined order.

3. In radio-telegraphy, the combination with an elevated conductor system, electric arcing means, a pair of arc-shunting circuits containing capacity and inductance adjusted to produce undamped electrical oscillations of a known wave length, one of said shunt circuits being associated with the elevated conductor system, another pair of arcshunting circuits adjusted to produce undamped electrical oscillations of a different wave length, one of said circuits being associated with the elevated conductor system, means for normally keeping the electric arc ing means in connection with the arc-shunting circuits that are unassociated with the elevated conductor system, means for breaking the aforesaid connections and making connections between the arcing means and the arc-shunting circuits that are associated with the elevated conductor system in a predetermined order and for equal intervals of time so that the elevated conductor system emits signals composed of elements equal in time value but differing in wave-length, and means for recording the order in which the oscillation producing systems render the elevated conductor system emissive.

In testimony whereof I affix my signature Witnesses A. DITTMAR,

J. G. H. GREY. 

